'''John William Strutt, 3rd Baron Rayleigh''' (; 12 November 1842 – 30 June 1919) was a physicist
who, with William Ramsay
, discovered argon
, an achievement for which he earned the Nobel Prize for Physics
in 1904. He also discovered the phenomenon now called Rayleigh scattering
, which can be used to explain why the sky is blue, and predicted the existence of the surface wave
s now known as Rayleigh wave
s. Rayleigh's textbook,'' The Theory of Sound'', is still referred to by acoustic engineers today.